No. 418.] NOTES ON LIVING NAUTILUS. 829 
eye protrudes conspicuously, but not, however, beyond the 
plane of the surface of the shell; its lower rim lies more or 
less within the lateral indentation of the shell's aperture. 
This indentation, as will later be seen, is apparently a provision 
to enable the animal to see, even when largely retracted. The 
tip of the siphon is also seen to protrude (S), and between it 
and the hood lie the closely arranged oral tentacles. When the 
animal is in this position 
the proximal ends of the 
tentacles appear long, 
narrow, and moderately 
well rounded ; the distal 
portions taper out deli- 
cately, the tips extended 
and weaving together, 
somewhat as shown in 
the figure. Examining 
a similar specimen from 
in front (Fig. 10), we 
observe a more or less 
regular arrangement of 
these tips of the tenta- 
cles; they cluster to- 
gether, lying in the main 
in front of and almost Fico. Vae patio ret 1a position. 
concealing the opening 
of the mouth. In this position the shape of the dorsal surface 
of the hood is well shown ; there is a median flattened tract 
from which the sides shelve away, moulding the hood to ue 
whorl of the shell and to the region of the eyes and tentacles. 
Looking at a specimen from above, we obtain the appearance 
shown in Fig. 12. ` This, however, pictures a more retracted 
Stage. It will be seen that the hood is neatly adjusted to the 
outline of the aperture of the shell. Anteriorly the distal ends 
of the tentacles protrude in a tuft and are arranged quite 
symmetrically.1 
‘Willey (Q. 7. M. S. 1898, Pl. X) figures them in complete extension, diverg: 
ing widely at the sides of the head, and still symmetrical in position. 
